But my partner's graphics card is fried and he's running on integrated now. I spent the last 2-3 days getting the isometric version running.
It runs at 60 FPS on my mom's 2007 desktop with a 20x20 map without any culling, but 300 on my laptop on integrated and 400-500 on discrete.
The 3D version (version C) runs at 150 on integrated and 300 on discrete on my laptop with a 60x60 map full of buildings and units. I don't want to spend the remainder of my summer getting a 2D version up to the same level as the 3D version though. So I'm going to work on version C on my own for now. Maybe next summer I'll work on D or maybe my partner will get a new videocard.
As for the economics, I've created a "demand tree" that figures out what buildings need to be built to support a certain population of labourers. This is not as simple as arithmetic because there might be dependency loops, but it doesn't really require anything more than arithmetic. It doesn't take into account transportation and infrastructure yet, so refineries, gas stations, harbours, roads, powerlines, and crude oil pipelines are not included yet. But it places the buildings on the map in order of their requirement, so it's an interesting visual, seeing the resulting composition of buildings based on the input and output quantities I enter for the building types.
Eventually the demand tree will be used to figure out the optimal prices and wages to set, taking into account local constraints of competition.